Field of the Invention
The present invention relates to an ink jet printing apparatus and an ink jet printing method.
Description of the Related Art
Ink jet printing apparatuses have been known which print images by repeatedly performing print scanning in which ink is ejected to a unit region of a printing medium by driving printing elements while relatively moving a printing head including a printing element array in which a plurality of printing elements which generate thermal energy for ejecting ink are arranged, and sub scanning in which the printing medium is conveyed. Such ink jet printing apparatuses of a so-called multipass printing method for forming images by performing a plurality of print scanning operations for a unit region has been known.
With such ink jet printing apparatuses of the multipass printing method, it has been known that printing is performed by using only some of the plurality of printing elements in the printing element array. For example, Japanese Patent Laid-Open No. 2011-025693 discloses a technique for performing printing by driving only printing elements which eject ink to a unit region in latter-half scanning for a printing element array which ejects ink containing color materials and driving only printing elements which eject ink to a unit region in former-half scanning for a printing element array which ejects ink not containing color materials. With such a printing method, ink ejection may be controlled such that ink not containing color materials can be provided to a printing medium earlier than ink containing color materials.
Meanwhile, with ink jet printing apparatuses which eject ink by thermal energy, it has been known that ink kogation occurs by thermal energy at driving of a printing element and the kogation is deposited on the surface of the printing element. In the case where such deposition of kogation occurs, the ejection characteristics including the ejection speed and the ejection amount of ink from the corresponding printing element differ from those of a printing element on which kogation is not deposited. In the case where the number of driving times varies among a plurality of printing elements in a printing element array, such as, for example, in the case where only some of the plurality of printing elements are driven as described above, the amount of kogation deposited varies among the printing elements after printing is performed. If printing is performed again by driving both the printing element on which kogation is deposited and the printing element on which kogation is not deposited in a state in which nonuniformity of kogation occurs, the quality of an image obtained may be degraded by the above-mentioned variations in the ejection characteristics.
Japanese Patent Laid-Open No. 8-039825 describes a technique for performing so-called aging processing in which the number of driving times is counted for each printing element, and the printing element is driven for each printing element in accordance with the counted number of driving times after printing is performed, so that uniformization is achieved for kogation discharge and smooth application of ink. According to the technique described in Japanese Patent Laid-Open No. 8-039825, a larger number of driving times in the aging processing is required for a printing element with a smaller number of driving times at the time of printing. By performing such aging processing, the ejection amount may become uniform among a plurality of printing elements within a printing element array. Therefore, a degradation in the image quality caused by variations in the above-mentioned ejection characteristics may be suppressed.
However, in the technique described in Japanese Patent Laid-Open No. 8-039825, the number of driving times at the time of printing is counted for each of a plurality of printing elements within a printing element array, and the number of driving times of aging is determined for each printing element. Therefore, in the case where a large number of printing elements form a printing element array or a large number of printing element arrays are used, the load of data processing increases in order to count the number of driving times of each printing element.
Furthermore, in the case where printing is performed using the technique described in Japanese Patent Laid-Open No. 2011-025693, the degree of kogation is not uniform between a printing element for which driving is defined and a printing element for which non-driving is defined. Meanwhile, nonuniformity of the degree of kogation among printing elements for which driving is defined is not very significant, and therefore a degradation in the image quality among the printing elements driven is not noticeable. However, according to the technique described in Japanese Patent Laid-Open No. 8-039825, the number of driving times for aging is calculated from the number of driving times for each printing element even for the printing elements for which driving is defined, and therefore the load required for data processing may unnecessarily increase.